Infiltrating leukocytes confound the detection of E-cadherin promoter methylation in tumors
Section snippets
Materials and methods
Tumor and normal breast material. Breast tumor tissues were obtained from the Rijnland Hospital (Leiderdorp) and the Leiden University Medical Center. Material was used only with the patient’s consent. The histology of the tumors was reviewed by a pathologist (VTHMBS). Breast tissue from a cosmetic breast reduction surgery sample was obtained from the Rijnland Hospital (Leiderdorp). Samples were snapfrozen in cooled (−70 °C) isopentane for DNA isolation or embedded in paraffin wax for
No correlation between E-cadherin expression and methylation-specific PCR fragments in primary breast tumors
We determined the methylation profile of part of the CDH1 promoter using the MSP method on 19 primary breast tumors: 7 ductal carcinomas, 11 lobular carcinomas, and 1 ducto-lobular carcinoma. E-cadherin protein expression in these tumors has been determined by immunohistochemical staining (Table 1). This set of breast tumors was selected for the absence of CDH1 mutations as detected by single-strand conformation polymorphism and DNA sequencing of the coding sequence and reported previously [10]
Acknowledgements
We thank Dr. J. Calame (Department of Pathology, Rijnland Hospital, Leiderdorp) for providing tissue from a cosmetic breast reduction surgery. Dr. R. van Soest (Department of Hematology, LUMC) is acknowledged for generously providing leukocytes. Activated T-cells were kindly donated by Drs. T.M. Holling and P.J. van den Elsen (Department of Immunohematologie and Blood Transfusion, LUMC). We acknowledge Dr. C.P. Verrijzer (Department of Molecular Cell Biology, LUMC) for useful discussion. Dr.
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